The desirability of a unitary pack containing a choice of smoking tobacco products having different flavor notes is apparent. Unfortunately, due to the volatility and mobility of certain flavorants causing a transfer of the flavorant from one smoking tobacco product to another during processing and storage, such a single unit/dual or multiple choice pack has not been practicable.
Menthol, which is a flavorant commonly used and widely accepted as a flavorant for smoking tobacco products, shows a particularly high degree of volatility and mobility resulting in a transfer of menthol flavor from one tobacco product to another. In addition, the odor of menthol permeates most wrappers.
In order to reduce the volatility and mobility and the migration of menthol resulting therefrom, it has been suggested that menthol be incorporated into tobacco as part of a less volatile compound, which upon burning of the tobacco is decomposed to yield menthol.
For example, Bavley et al., U.S. Pat. No. 3,312,226 describes the incorporation of menthol into tobacco as the l-menthyl carbonate ester of various alcohols, such as linalool. These carbonate esters release menthol upon pyrolysis. However, these simple carbonate esters, like menthol itself, are somewhat susceptible to migration in tobacco and thus can impart a menthol flavor to unmentholated smoking tobacco products in the same pack. Additionally, the second alcohol of the carbonate ester can undergo chemical alteration during pyrolysis, resulting in undesired chemical fragments which can add a chemical aftertaste.
In Mold et al., U.S. Pat. No. 3,419,543 and 3,332,428, mixed carbonate esters of a flavorant, preferably menthol, and a polyhydroxy compound such as a monosaccharide, disaccharide, trisaccharide, polysaccharide, or glycol are described as a means for binding menthol in the tobacco in a relatively non-volatile form. Similarly, in Kallianos et al., U.S. Pat. No. 3,449,452, the incorporation of various other flavorants including vanillin and phenethyl alcohol, into tobacco in the form of relatively non-volatile mixed carbonarte esters of polyhydroxy compounds selected from the group consisting of mono-, di-, tri- and polysaccharides and glycols is described. However, since the alcohol linkages of these polyhydroxy compounds are only primary or secondary in character, the efficiency with which the flavorant can be regenerated upon pyrolysis is limited. In addition, when Mold menthol-release agents which would release a high proportion of menthol per unit weight were utilized, it was discovered that menthenes were often produced in addition to menthol, resulting in a bitter tasting tobacco smoke. Further, some of the Mold flavor-release agents are unstable to aging and have been found to steadily release menthol over a period of time.
The Rundberg, Jr., et al. U.S. Pat. No. 3,887,603 employs carbonate ester polymers for the controlled release of menthol. These menthol-release agents ae polymeric l-menthyl carbonate esters characterized by the presence of a pendant tertiary alcohol ester linkage thus making menthol release the preferred decomposition mechanism upon pyrolysis. These polymers lack substantial volatility and/or mobility at ambient temperature within a tobacco composition. Even these polymers, however, do not release menthol with the maximum efficiency.
Other methods for incorporating menthol and other flavorants into smoking tobacco products have also been described in U.S. Pat. Nos. 3,111,127, 3,126,012, 3,128,772, 3,139,888, 3,452,677, 3,580,259, 3,589,372, 3,625,224, 3,772,516, 3,750,674, 3,879,425, 3,881,025, 3,884,247, 3,890,981, 3,903,900, 3,914,451, 3,915,175, 3,920,027, 3,924,644, 3,937,288 and 3,943,943.
Nowhere, however, has there been described a flavorant-release composition which exhibits optimally efficient and uniform flavor-release characteristics while being sufficiently non-migratory to permit packaging of a smoking tobacco product containing the composition with other smoking tobacco products to which addition of the flavor of the composition is not desired. There has, thus, remained a need for improved flavorant-release composition for incorporation in smoking tobacco products which compositions would permit packaging of smoking tobacco products containing a flavorant with other smoking tobacco products without imparting the flavorant's taste to the latter products while upon pyrolysis uniformly and efficiently releasing the flavorant from the smoking product in which they are incorporated, without adding deleterious flavoring effect thereto.
Accordingly, it is the main object of this invention to provide a unitary pack of smoking tobacco products in which some of the smoking tobacco products are treated with a flavorant-release agent which is characterized by a substantial lack of volatility and/or mobility within a tobacco composition at ambient temperature, whereby, even after processing and storage, the untreated smoking tobacco products in the pack do not acquire the taste of the flavorant and the products containing the flavorant-release agent do not deliver significantly less flavor than smoking tobacco products treated with the flavorant itself.
It is a further object of the present invention to provide a unitary pack of smoking tobacco products in which a flavorant is incorporated in some of the smoking tobacco products as a polymeric alcohol flavorant-release carbonate ester resin which releases the alcohol flavorant when heated and does not have a deleterious effect on the flavor of the products.
It is another object of the present invention to provide a means for packaging flavored smoking tobacco products with smoking tobacco products which are unflavored or contain other flavorants without a transfer of flavorant between the smokin tobacco products while maintaining an optimally efficient release of flavorant upon normal smoking of the products thereby permitting the amounts of flavorant required to be added to a tobacco composition to be minimized.
Other objects and advantages of the present invention shall become apparent from the following description and examples.